Normal Ranges of 24-Hour pH-metry Established in Corrected Esophageal Atresia

Bergmeijer, Jan-Hein L. J.; Bouquet, Jan*; Hazebroek, Frans W. J.

ABSTRACT

Background: This study was undertaken to determine baseline values of 24-hour pH-metry in children who had undergone correction for esophageal atresia.

Methods: A 24-hour pH-metry without medication was conducted in 13 patients with an uncomplicated postoperative course after correction of esophageal atresia. The pH-metry was performed in the hospital with a flexible glass electrode.

Results: The mean reflux index was 4.08%, the mean total number of reflux periods with a pH less than 4 was 21, and the mean number of periods of pH less than 4 lasting longer than 5 minutes was 2.5.

Conclusions: Twenty-four-hour pH-metry values in asymptomatic esophageal atresia patients are the same as in children from the same age group with normal anatomy.

Children who have undergone successful correction of esophageal atresia often have gastroesophageal reflux, which, in turn, is a major cause of complications, such as anastomotic stricture, reflux esophagitis, aspiration pneumonia, and even near-sudden infant death syndrome (1-3).

The decision whether surgical or medical treatment or no treatment at all is indicated should be applied on suspicion of reflux and must be based not only on good clinical grounds, but on objective investigations as well. Barium contrast study of the esophagus and stomach, esophagoscopy, and 24-hour pH-metry are the standard methods for the diagnosis and evaluation of pathologic gastroesophageal reflux in normal neonates and children. Even more strongly, pH-metry is considered the gold standard for defining the duration and severity of reflux (4-7). Normal ranges have been established for these groups (8,9), but not for patients with corrected esophageal atresia.

For this reason, we investigated 24-hour pH-metry values measured early after operation in 13 patients whose postoperative course during the first year after correction of esophageal atresia was completely uneventful.

PATIENTS AND METHODS

From January 1994 through November 1996, 48 patients with esophageal atresia were treated in the Sophia Children's Hospital. According to the criteria of Gross, three patients had type A atresia, and underwent colonic interposition. Two patients had H-type fistula and the other 43 had classic type C with tracheoesophageal-fistula. In accordance with our treatment protocol, they all underwent pH-metry studies between 8 and 16 weeks after surgery. Twenty-four patients had reflux-associated complications, such as failure to thrive, stricture of the anastomosis, respiratory tract infections, or tracheal malacia. All underwent prolonged medical antireflux therapy, and eight of them underwent a Nissen fundoplication.

Of the remaining 19 patients with an uncomplicated short- and long-term postoperative course, followed up for at least 1 year, 13 had undergone a complete and reliable 24-hour pH-metry without medication. In four of the remaining six patients, pH-metry was performed much later than 16 weeks after surgery, and consent for the investigation was refused by the parents of the two remaining patients. The pH-metries had been performed in our hospital, using a flexible glass electrode with internal reference electrode (Escolab, Maarssenbroek, The Netherlands) connected to a bedside computing system (UPS-2020/Orion, MMS B.V. Holland, Enschede, The Netherlands). All patients were fed their normal formulas during pH-monitoring.

RESULTS

The mean gestational age of the 7 girls and 6 boys was 36 weeks (range, 31-40 weeks). Six patients had been born at term, and 7 were premature. Only 2 of the 13 patients showed (minor) anastomotic tension, and only 1 had minor leakage of the anastomosis. All patients were supported by postoperative ventilation, which we consider essential after a major thoracotomy. Ten patients were ventilated for 2 to 5 days, and 3 premature infants for 22, 28, and 60 days. In all but 1 patient, the site of the esophagogastric junction as assessed by a barium contrast study was normal, although all children had some provocative reflux, which we did not consider to be abnormal.

The pH-metries were performed at a mean of 12.7 weeks (range, 8-16 weeks; median, 12 weeks) after surgery. The mean reflux index (percentage of time with pH <4 during 24 hours) was 4.08% (range, 1-9.8%; median, 3.3%). Mean total number of reflux periods with a pH less than 4 was 21 (range, 3-60; median, 17). Mean number of periods of pH less than 4 lasting longer than 5 minutes was 2.5 (range, 0-9; median, 2). Figure 1 shows the correlation between gestational age of the patients and the reflux index.

FIG. 1. Relation between reflux index values and gestational age

DISCUSSION

Normal ranges of 24-hour pH-metry in asymptomatic healthy newborns and children up to the age of 18 months have been well established by Vandenplas and Sacre-Smits (8,9). Such ranges had not yet been established in patients with a corrected esophageal atresia. In several studies, pH-metry was conducted in symptomatic atresia patients, and the results were compared with normal values in asymptomatic children and newborns, assuming that these are the same as in asymptomatic patients with esophageal atresia (9,10). Because the incidence of gastroesophageal reflux in patients with atresia (30-50%) is higher than in the normal population (1,3), because of motility disorders of the distal esophagus, alteration of the angle of His, and delay of esophageal clearance of acid, a set of normal values as a reference would help to establish whether a symptomatic patient with atresia has pathologic reflux, and whether medical or surgical treatment is preferable.

In this study, the values for the age group between 8 and 16 weeks were comparable to those found by Vandenplas and Sacre-Smits (8,9): The mean reflux index in our series was 4.08%, versus 4.18% in normal children 2.5 to 4.5 months of age in the series of Vandenplas and Sacre-Smits. The mean total numbers of periods with pH less than 4 was 21 versus 20, and the mean number of periods with pH less than 4 for longer than 5 minutes was 2.5 and 3.2, respectively. In this small group of patients, we could not find a negative correlation between prematurity and the extent or severity of reflux as shown in Figure 1.

In conclusion, from the results in this study in 13 asymptomatic patients with corrected esophageal atresia, it appears that 24-hour pH-metry values are the same as in asymptomatic children with normal anatomy. Therefore, they can be used for further diagnosis and evaluation of patients in case of clinical suspicion of pathologic gastroesophageal reflux after correction of esophageal atresia.